I've had similar experience while dealing with Comcast installation techs.
The installation tech insisted that he needed to use my computer to complete the installation. My computer (running Debian, so using it was out of the question anyway) was sitting right in front of both of us. I told him that he didn't need to use it (which is true) and he insisted that he did. Then I told him that I did not have a computer. We could both see it, but only by insisting that I did not have a computer was I able to get him to complete the installation without using it (he made a short phonecall, and that was it).
The installation tech insisted that he needed to use my computer to complete the installation. My computer (running Debian, so using it was out of the question anyway) was sitting right in front of both of us. I told him that he didn't need to use it (which is true) and he insisted that he did. Then I told him that I did not have a computer. We could both see it, but only by insisting that I did not have a computer was I able to get him to complete the installation without using it (he made a short phonecall, and that was it).